This invention relates to support chairs for foundations and, in particular, where a foundation includes an uppermost slab part of which is supported on lost formwork.
In particular, there is a difficulty associated with lost formwork in which the formwork is comprised of a disposable material such as corrugated cardboard.
While such material is effective from a cost point of view, there can, nonetheless, be some disadvantages insofar that if the lost formwork is in the form of rectangularly shaped boxes with an uppermost surface which is substantially horizontal, there can be difficulties if substantial loads are applied during pouring of the concrete.
One particular problem occurs insofar that reinforcement fabric in either the form of mesh or single rods need to be supported a given distance above a lowermost surface and this is achieved by supporting the mesh of rods by means of a plurality of support chairs.
Each chair, in a conventional system, includes an uppermost open slot and a lowermost planar surface by which the chair rests on a supporting surface being the lost form work.
Such devices, as presently exist, have not been found to be especially useful in that when a heavy load is pulled across the fabric, these will tend to shift the fabric and depress the top of the box so that the chairs will separate from a supporting position losing any relative relationship in position with the result that the fabric can be left without support and fall to a lowermost level or it requires a very significant time for a worker to relocate these on an ongoing basis.